Motor vehicles including conventional drivetrains emit sounds during acceleration events, deceleration events, and gear changes. Many consumers have come to rely on these sounds as a sign of proper mechanical function. Changes in these sounds may indicate, to certain consumers, that a problem may exist in the drivetrain. Other consumers may associate the sounds with a desired performance level of the motor vehicle. Certain sounds are associated with “high performance” vehicles. An absence of the sounds may detract from an overall enjoyment of the motor vehicle.
Many newer motor vehicles include electric, hybrid electric or fixed gear drivetrains. Electric drivetrains produce little noise during operation. Noise produced by hybrid electric drivetrains is distinct from noises associated with more conventional drivetrains. Fixed gear drivetrains do not include shift points and thus lack any sounds associated therewith. Many users of newer automobiles are uncomfortable with the lack of, or change in, sound produced by electric and hybrid electric motor vehicles. Accordingly, it is desirable to provide a system for producing drivetrain sounds that consumers have come to expect to perceive when operating a motor vehicle. There are also times when motor vehicles produce narrow band sounds (often perceived as tones) that occupants in the vehicle find incongruous with the operation of the vehicle. At other times tones can be produced that are understandable but have a frequency range and amplitude that may detract from an overall vehicle experience.